Browsing by Subject "waste heat utilization"

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Access status: Open Access ,
The RWE Power WTA process (Fluidized bed drying) as a key for higher efficiency
(Wydawnictwa AGH, 2011) Klutz, Hans-Joachim; Moser, Claus; Bargen, Nikolaus von
RWE is a large utility company focused on Germany and Europe. About 10,000 MW of the generating capacity is based on lignite which is mined in three large open cast mines in the Rheinland. This lignite with a heat content of around 9000 to 10000 KJ/kg has a moisture content of about 55%. This high moisture content needs to be removed prior to any further utilisation. It is also responsible for a relatively high specific $CO_{2}$ emission. RWE Power has developed the WTA Process (Fluidized bed drying with internal waste heat utilisation) which offers important advantages in comparison against the conventional drying technologies: much better thermal efficiency, less $CO_{2}$ emissions, much better flexibility, chance for water recovery and lower costs. The principle method of this process is the drying of lignite in a drying chamber in a fluidized bed heated with low pressure steam of about 4 bar and recovering of the energy content in the vapour. This technology will be used to dry the raw lignite for the new proposed 1000 MW thermal units and thus increase efficiency of the entire power station by about 4 to 6% points. This will result in a $CO_{2}$ reduction of about 500 000 tonnes per 1000 MW unit per year. At the site of the BOA unit at Niederaussem a large scale prototype plant with a throughput capacity of 210 tonnes per hour (100 tph of evaporation capacity) was built and is now in its trial period. First operational results will be shown.